Numerous knife sharpening systems are available, with many typically including a clamping device for holding a knife in a fixed position and a hand-held sharpening hone or block. The sharpening block may be slid across the cutting edge of the knife at a prescribe angle. Prior art systems are flimsy, limited in adjustment and/or selection of the prescribed angle, unstable, and incapable of setting a consistent relative position and angle between the cutting edge of a knife and the sharpening block over repeated sharpening sessions. A number of prior art systems will now be described.
Longbrake, U.S. Pat. No. 7,144,310, discloses an adjustable knife sharpener apparatus. The apparatus includes a clamping mechanism operable to secure a knife blade, and at least one adjustable guide rod coupled to the clamping mechanism to adjust a sharpening angle of the knife sharpener apparatus. The apparatus further includes a first guide rod coupled to a first clamp member, and a first infinitely adjustable guide loop coupled to the first guide rod to adjust a sharpening angle of the knife sharpener apparatus. Longbrake lacks, among other things, a means of securely affixing a guide rod in an adjustable fixed position wherein the guide rod is coupled to a stable base with a clamping mechanism, as well as a means for repeatably and verifiably controlling the depth and alignment of the knife blade with respect to the clamping mechanism and the sharpening blocks.
LeVine, U.S. Pat. No. 4,512,112, discloses a sharpener clamp construction comprising first and second clamp members having a first longitudinal axis and first and second ends, respectively, first and second jaws at sais first ends of said first and second clamp members, respectively, for clamping a knife with a second longitudinal axis extending transversely to said first longitudinal axis. LeVine further discloses first and second guide member means formed integrally with and extending outwardly from said first and second clamp members, respectively, at said second end, and a plurality of apertures in said first and second guide member means at different distances from said second end for receiving a guide rod attached to a sharpener stone holder. Levine lacks, among other things, a means of securely affixing a guide rod in an adjustable fixed position wherein the guide rod is coupled to a stable base with a clamping mechanism, as well as a means for repeatably and verifiably controlling the depth and alignment of the knife blade with respect to the clamping mechanism and the sharpening blocks.